DE19911041A1 - Flexible and absorbent carriers for treating the skin equipped with nanoparticle dispersions - Google Patents

Abstract

The invention relates to flexible, absorbent carriers which are provided with cosmetic or dermatological agents or preparations for treating the skin, e.g. moist cleansing tissues or cellulose pads and which contain agents or preparations in the form of nanoparticles with an average particle diameter of less than 300 nm that are solid at a temperature of 40 DEG C. The nanoparticles can, for example, consist of waxes, optionally mixed with lipophilic, cosmetic or dermatological agents, sterols, chitosans or inorganic oxides.

Description

The invention relates to flexible and absorbent substrates with cosmetic or dermatological active ingredients or preparations in the form of very fine particles are equipped in the nanometer range and can be used for cleaning, caring or therapeutic treatment of the skin.

A lot is used for the cosmetic and therapeutic treatment of the skin different fixed carriers, but which always have a certain flexibility and absorbency must have so that they are in the treatment of the body parts to be treated adapt well and, if necessary, can absorb dirt and sweat and exudate. The Classic areas of application of such carriers are e.g. B. tampons and cellulose pads as well Wet wipes for skin cleaning and make-up removal, face masks for cosmetic treatment of the facial skin or therapeutic, e.g. B. transdermal active or cosmetic plasters for local long-term skin treatment.

Equipping such carriers with cosmetic or dermatologically effective ones Until now, composing has mainly been done by moistening with aqueous preparations, e.g. B. solutions or emulsions of cosmetic or therapeutically active substances or Fragrances. The equipment with water-insoluble oils had to be emulsions and dispersions of these substances in water. The use of normal, coarse-grained The disadvantage of emulsions and dispersions is that they are spread over a very large area Carrier must be applied so that the water-soluble emulsion droplets  be evenly distributed on the substrate, otherwise it would be filtered and Chromatography effects on the absorbent substrate to an uneven Distribution of active substances and oils is coming.

In EP O 613 675 A1 it had been proposed to use particularly low-viscosity emulsions Use wet wipe equipment. According to WO 97/07195 A1 Cleaning emulsions are used, the particles of which are not larger than 1 µm.

However, it has been shown that cleaning wipes soaked in emulsified oils cause problems during use because the skin is often too oily and the wearer himself looks sticky. These problems are addressed by the subject of the present invention solved in a satisfactory manner.

The invention relates to flexible and absorbent, with cosmetic or dermatological agents or preparations equipped carriers for the treatment of Skin that forms active ingredients or preparations that are solid at 40 ° C of nanoparticles with an average particle diameter of less than 300 Nanometers (nm) included.

As a flexible and absorbent carrier in the sense of the invention, z. B. carrier from Textile fibers, collagen or polymer foams. As textile fibers can both Natural fibers such as cellulose (cotton, linen), silk, wool, regenerated cellulose (Viscose, rayon), cellulose derivatives as well as synthetic fibers such. B. polyester, Woven polyacrylonitrile, polyamide or polyolefin fibers or mixtures of such fibers or used non-woven. These fibers can become absorbent cotton pads, Nonwovens or be processed into woven or knitted fabrics.

Collagen fibers or freeze-dried collagen foams are e.g. B. as an active ingredient carrier for Suitable for face masks and wound dressings. Also flexible and absorbent polymers Foams, e.g. B. polyurethane foams and polyamide foams are suitable substrates.  

Carrier substrates which are considered to be absorbent in the sense of the invention are those which 20 ° C at least 10 wt .-%, based on the dry weight, adsorptive or water can bind capillary. However, preference is given to those carriers which have at least 100% by weight Can bind water adsorptively and capillary.

The active substances or preparations suitable according to the invention should be solid at 40 ° C. so that they remain as solid particles at normal temperature and also at body temperature available. Liquid active ingredients may also be present, but these should be included in Form of a solid preparation at 40 ° C, e.g. B. present as a solution in a wax.

All substances which are cosmetic or therapeutic, e.g. B. exert a dermatological effect on the skin or connective tissue. As a cosmetic Effect can, for. B. skin-softening, skin-smoothing, skin-moisturizing, lipid-replenishing, antiperspirant, deodorant and fragrant effects become. As cosmetic active ingredients are therefore z. B. wax, essential fatty acids (Tocopherol, Retinol), Biotin, Panthenol, Ceramide, Chitosan, Phytosterine or also inorganic substances such as B. silicas, aluminum silicates (bentonites, hectorites), Aluminum oxide hydrate (boehmite), aluminum chlorohydrate, kaolin, talc, apatite, Zirconium dioxide, magnesium oxide, zinc oxide and other powder bases are suitable. Also coloring pigments, e.g. B. Iron oxide pigments may be included.

A preferably suitable nanopowder for finishing the carriers according to the invention is an aluminum oxide hydrate of the composition AlOOH.H ₂ O (boehmite) with a specific surface area of more than 200 m ² / g. This material is inexpensive and available in large quantities. A slight contamination with approximately 4-14% by weight aluminum acetate hydrate (Al (OCOCH ₃ ) ₃ H ₂ O is not disadvantageous for the purposes of the invention. The product is known as Disperal Sol P3 (Condea Chemie GmbH ) in trade.

By treating such nanoscale oxides, oxide hydrates or hydroxides with aqueous ones Carboxylic acids with 2-3 carbon atoms, especially with hydroxycarboxylic acids, e.g. B. with Lactic acid, these can be modified so that they form gel dispersions in water can form.  

Waxes can be understood to mean all natural or synthetically obtained substances that are solid and kneadable at 20 ° C, coarse to fine-crystalline and only change to a flowable state above 40 ° C without decomposition. Suitable substances of this type are e.g. B .:

• 1. natural waxes, namely:
  • a) vegetable waxes, which are divided into recent waxes such as Candelilla, Carnauba, Japan, Espartogras, Ourcoury waxes and fossil waxes such as montan wax, etc .;
  • b) animal waxes such as bees wax, shellac wax, walrus, lanolin (wool wax), pretzel fat, etc .;
  • c) mineral waxes (petroleum waxes) such as ceresin, ozokerite (earth wax), petrolatum, paraffin and micro waxes;
• 2. chemically modified waxes z. B. the oxidized from raw montan wax Products
• 3. synthetic waxes, also called synthetic waxes, e.g. B. the Fischer-Tropsch Paraffins obtained by air oxidation, selective Solvent treatment, esterification, saponification, etc. in a number of Hard waxes are transferred. Also polyethylene waxes, some of them High pressure polymerization of ethylene partly by cracking from the high molecular weight Low-pressure polyethylene are produced, as well as corresponding oxidized products, are synthetic waxes.
• 4. Also the esterification products of long-chain fatty alcohols with long-chain Fatty acids, e.g. B. cetyl palmitate, cetyl stearate, stearyl palmitate, behenyl palmitate and the like. a. such as the saturated triglycerides, e.g. B. the hardened vegetable and animal fats such as e.g. B. Geh. Beef tallow, Geh. Palm fat, Geh. Castor oil are waxes in the sense of present invention.

As dermatological, therapeutic agents such. B. antimicrobial or antifungal substances, antiallergics, antiphlogistics, analgesics, circulation-promoting or local anesthetic substances.  

The cosmetic and dermatological active ingredients or preparations should be at 40 ° C be solid and in the form of nanoparticles with an average particle diameter of are less than 300 nm. Various methods have been known recently to get the most diverse substances in nanoscale distribution and in to convert stable aqueous dispersions.

EP 0 499 299 A2 describes a process for the production of crystalline particles organic, therapeutic agents by wet grinding in the presence of a Surface modifier described up to an average particle size below 400 nm. Another method is e.g. B. the evaporation process, in which the organic Compound dissolved in an organic solvent and in water in the presence of a surface-active compound is precipitated again, the organic Solvent is evaporated.

In the GAS process, a highly compressed gas or a supercritical fluid is injected into the Solution of the organic compound pressed. The fluid is absorbed and it there is a decrease in solubility and fine-particle precipitation of the connection. Also by injecting the organic compound solution into a supercritical fluid there are very finely divided droplets from which the solvent enters the fluid diffuses and the finest particles are precipitated (PCA process).

Also by injecting the solution of the organic compound into a supercritical one Fluid into the headspace or into a non-solvent that may contain a surfactant Preserved nanoparticles of the compound.

The inorganic nanoparticles mentioned can, if they are not already in the Manufacture as an aqueous dispersion, easily in water, preferably in the presence a surfactant or a polymeric protective colloid.

Waxes and lipids with melting points of 40-90 ° C can be z. B. after in EP O 506 197 A1 described method by dispersing in water in the presence of a Convert emulsifier into finely divided nanodispersions. In DE 43 37 030 A1 there is also a  Process for the preparation of wax dispersions by emulsification in the melt described according to the phase inversion process, in which wax particles with Particle sizes below 500 nm can be obtained.

Wax dispersions which are dissolved in the wax are also obtained by this process Active ingredients, e.g. B. tocopherols, retinols, panthenol and. a. included if you have such Active ingredients in the wax component dissolves. Examples of such dispersions are in Sample part listed.

In a preferred embodiment, the nanoparticles contained as equipment exist wholly or predominantly from waxes, optionally in a mixture with lipophilic cosmetic or dermatological active ingredients.

Also sterols and sterol esters, e.g. B. Soy phytosterol, β-sitosterol, β-sitosteryl laurate or β-sitosteryl stearate can be converted into nanoparticle dispersions by methods known from the literature. A suitable method for this purpose is e.g. B. the previously described RESS process (Rapid Expansion of Supercritical Solutions), in which a solution of the sterol in CO _{2 is} relaxed under supercritical conditions of pressure and temperature in an aqueous solution of a surfactant or protective colloid.

According to the same procedure, e.g. B. also chitosan, vitamins and esters of Vitamins, e.g. B. tocopherol succinate, are converted into nanoparticle dispersions. In a further preferred embodiment of the invention, the equipment consists of the nanoparticles contained in the carriers according to the invention entirely or predominantly Sterols, chitosans or derivatives of these natural products.

Inorganic substances with a cosmetic or therapeutic effect can also be in the form of nanoparticles in the carriers equipped according to the invention. Methods for producing such inorganic nanoparticles are e.g. B. from EP 711 217 A1 (Nanophase Technologies Inc) known, suitable oxides are under the trademark Nano Tek® in stores. A process for the preparation of aqueous suspensions of nanoscale inorganic compounds by precipitation from dissolved precursors in aqueous solution in the presence of surface-blocking surfactants or polymers, e.g. B. from WO 96/34 829 known. A process for the production of a very fine suspension in water sparingly soluble calcium salts by precipitation from water soluble calcium salts and  water soluble phosphate or fluoride salts is e.g. B. Subject of the German Patent application No. 198 58 662.0.

All mentioned inorganic oxides, hydrated oxides, phosphates and others are suitable in Form of aqueous dispersions excellent for finishing the carrier according to the invention. You have z. B. an odor absorbing, e.g. T. also sweat-absorbing effect and leave the skin in a dry, well-groomed condition.

In a further preferred embodiment of the invention, the equipment consists of the nanoparticles contained in the carriers according to the invention entirely or predominantly inorganic oxides, e.g. B. from boehmite.

The carrier substrates according to the invention are equipped in such a way that the absorbent, flexible carrier substrates, preferably made of textile fibers, collagen or polymeric foams with dispersions of cosmetic and dermatological Active substances and with an average particle size of less than 300 nm in a non- Treated solvent and if necessary dries.

Water is preferably used as the non-solvent if the active substances are therein no significant solubility or a solubility of less than 0.01% by weight at 20 ° C exhibit. However, other, preferably low-boiling solvents, e.g. B. Ethanol or isopropanol, ethers, ketones, hydrocarbons or cyclosiloxanes as Non-solvents can be used.

The carrier substrates are preferably treated with dispersions whose Concentration of nanoparticles not higher than 10% by weight, preferably not higher than 5 % By weight, based on the dispersion, so that the viscosity of the dispersion is low, preferably remains below 1 / Pas (20 ° C).

The treatment (equipment) of the carrier substrates with the dispersion of the nanoparticles can by any method, e.g. B. by spraying, dipping and squeezing,  Soak or simply by injecting the dispersion into the carrier substrates respectively.

An advantage of nanodispersion over coarse-particle emulsions or dispersions is particularly evident in the fact that these dispersions are due to the capillary forces distribute evenly in the carrier without causing inhomogeneities due to Filtration or chromatography effects comes. In any case, after the Equipment distributes the active ingredient nanoparticles evenly in the carrier.

If the production of wet wipes, e.g. B. for make-up removal or as a baby wipe should be used as a non-solvent or as Water dispersion medium can be used; this can occur after treatment of the Carrier substrates remain wholly or partly on the carrier.

But when it comes to the equipment of e.g. B. tampons and cellulose pads or plasters, the dispersion medium should be removed by drying. This is especially then required if it is an organic solvent based on the Skin can cause unwanted reactions.

The carriers equipped according to the invention are particularly suitable as Wet wipes for cleaning sensitive skin and removing make-up, as face masks, for nourishing and regenerating skin care or as skin plasters, for local cosmetic treatment of oily, dry or wrinkled areas of skin. The contained active ingredients, e.g. B. vitamins, biotin, ceramides, phytosterols, chitosan or Waxes can easily penetrate into the upper skin layers in the form of nanoparticles and develop their effect there.

The following examples are intended to explain the subject of the invention in more detail:  

Examples

1. Production of wax nanoparticle dispersions

The production took place after the so-called. PIT (phase inversion temperature) process analogous to DE 43 37 030.

The dispersions were used to finish cellulose nonwovens to a content of approx. 3% by weight (approx. 1: 9) diluted with water. 5 g each of this dispersion were used Finishing of 100 g cellulose fleece used.  

2. Manufacture from nanoparticle dispersions

2.1 Boehmite (modified with lactic acids), average particle size 50 nm

2.2 hardened castor oil, nanoparticles of medium particle size 190 nm

Production: The nanoparticles 2.1 were prepared by boiling 120 g of Dispersal Sol P3 in a solution of 20 g lactic acid in 800 g water over 45 minutes and subsequent Freeze-drying made.

The nanoparticles 2.2 were produced using the RESS process with CO ₂ (known as castor oil). The products were obtained as an aqueous dispersion and used to finish cellulose fleece.

Claims (7)

1. Flexible and absorbent carrier equipped with cosmetic or dermatological active substances or preparations for the treatment of the skin, characterized in that active substances or preparations which are solid at 40 ° C. in the form of nanoparticles with an average particle diameter of less than 300 nm are used as finishing agents are included. 2. Carrier according to claim 1, characterized in that it is made of textile fibers, Collagen or polymeric foams are made. 3. Carrier according to one of claims 1 or 2, characterized in that the as Equipment contains nanoparticles entirely or predominantly from waxes, optionally in a mixture with lipophilic cosmetic or dermatological Active ingredients exist. 4. Carrier according to one of the claims 1-3, characterized in that the as Equipment contained nanoparticles entirely or predominantly from sterols, chitosans or derivatives of these natural products. 5. Carrier according to one of the claims 1-4, characterized in that the Equipment contained nanoparticles entirely or predominantly from inorganic Oxides exist. 6. A method for producing supports according to claims 1-5, characterized characterized in that one prefers absorbent, flexible carrier substrates Textile fibers, collagen or polymeric foams with dispersions of cosmetic and dermatological active ingredients with an average particle size of treated less than 300 nm in a non-solvent and optionally dries.   7. Use of the carrier according to one of the claims 1-5 as Wet wipe, face masks or skin patches.